Relation of operator volume and experience to procedural outcome of percutaneous coronary revascularization at hospitals with high interventional volumes

Abstract

Background: Although an inverse relation between physician caseload and complications has been conclusively demonstrated for several surgical procedures, such data are lacking for percutaneous coronary intervention, and the ACC/AHA guidelines requiring > or = 75 cases per year for operator "competency" are considered by some physicians to be arbitrary.

Methods and results: From quality-controlled databases at five high-volume centers, models predictive of death and the composite outcome of death, Q-wave infarction, or emergency bypass surgery were developed from 12,985 consecutively treated patients during 1993 through 1994. Models had moderate to high discriminative capacity (area under ROC curves, 0.65 to 0.85), were well calibrated, and were not overfitted by standard tests. These models were used for risk adjustment, and the relations between both yearly caseload and years of interventional experience and the two adverse outcome measures were explored for all 38 physicians with > or = 30 cases per year. The average physician performed a mean +/- SD of 163 +/- 24 cases per year and had been practicing angioplasty for 8 +/- 5 years. Risk-adjusted measures of both death and the composite adverse outcome were inversely related to the number of cases each operator performed annually but bore no relation to total years of experience. Both adverse outcomes were more closely related to the logarithm of caseload (for death, r = .37, P = .01; for death, Q-wave infarction, or bypass surgery, r = .58, P < .001) than to linear caseload.

Conclusions: In this analysis, high-volume operators had a lower incidence of major complications than did lower-volume operators, but the difference was not consistent for all operators. If these data are validated, their implications for hospital, physician, and payer policy will require exploration.